The main theme of The Monkeys Paw is to be careful what you wish for. The purpose is to show the readers that when you make a wish you can have bad preducaments come back to you after you make that wish, You can have something taken away from you for the wish that you made. It also has another point, and that is to never interfere with fate. If you interfere with fate you may never know what was actually supposed to happen instead of what did because of the wish that you had made.
This is not a Paw but it can still grant wishes. In the Monkeys Paw there were three wishes granted, all of which came true with very harsh things given or done to the person/people who made the wish.
In the Monkeys Paw this bag of "pounds" is relatable because it was one of their main wishes. Inspite of there wish for two hundred pounds their son died at his formal job.
All the wishes that had been granted in the Monkeys Paw is what made it a tale. Most tales have morals and this one did. Be careful what you wish for, because things are not always as they seem.